Hierarchically magnetic Ni–Al binary layered double hydroxides: towards tunable dual electro/magneto-stimuli performances

Li Deng,Wenpeng Jia,Wen Zheng,Hao Liu,Degang Jiang,Zimeng Li,Yu Tian,Wenling Zhang,Jingquan Liu 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.58 No.-

Ni–Al layered double hydroxides (Ni–Al LDHs) are adopted as an electrorheological (ER) materialascribed to their special layered structure, ample polarizable groups and good dispersibility. Themagnetite nanoparticles (Fe3O4 NPs) are utilized as classical magnetorheological (MR) materials onaccount of their excellent paramagnetic property. In this work, we report the rational design of highperformanceER/MR materials by integrating the structural merits of Fe3O4 NPs onto a binary layeredstructure system. The obtained Fe3O4/Ni–Al LDH NCs dispersed in silicone oil displayed appealing dualER/MR performances. The work opens a new path toward novel stimuli-responsive materials forindustrial applications.

Effects of Annealing Pressures on the Ordering and Microstructures of FePt

Xiaohong Li,Zhaodi Feng,Yang Li,Wenpeng Song,Qian Zhang,Baoting Liu 한국자기학회 2013 Journal of Magnetics Vol.18 No.4

FePt:Ag (100 nm) nanocomposite thin films were prepared on naturally-oxidized Si substrates by dc magnetron sputtering at room temperature. X-ray diffraction (XRD) and transmission electron microscopy (TEM) are used to investigate the effects of annealing pressures on the ordering processes and microstructures of these films. The average sizes for the L10 ordered domains and the FePt grains are reduced to d = 9 nm and D = 13 nm from d = 19 nm and D = 34 nm, respectively, when the annealing pressure is enhanced to 0.6 GPa from room pressure at 873 K. Furthermore, the size distribution is improved into a narrow range. With increasing pressure, the coercivity of L10-FePt:Ag thin films decreases from 15.1 to 7.6 kOe. In the present study, the effects of high pressure on the L10 ordering processes and microstructures of FePt:Ag nanocomposite films were discussed.

Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement <i>via</i> Charge Separation

Hou, Wenpeng,Zhao, Ning-Jiu,Meng, Dongli,Tang, Jing,Zeng, Yi,Wu, Yu,Weng, Yangziwan,Cheng, Chungui,Xu, Xiulai,Li, Yi,Zhang, Jian-Ping,Huang, Yong,Bielawski, Christopher W.,Geng, Jianxin American Chemical Society 2016 ACS NANO Vol.10 No.5

<P>The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.</P>

Cactus-like double-shell structured SiO2@TiO2 microspheres: Fabrication, electrorheological performances and microwave absorption

Xuqiang Ji,Wenling Zhang,Wenpeng Ji,Xiaoxia Wan,Yutian Wang,Li Deng,Jingquan Liu 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-

The cactus-like double-shell structured SiO2@TiO2 microspheres (CDS SiO2@TiO2 microspheres) withhigh dielectric properties were successfully fabricated and utilized as high-performance electrorheological(ER)fluids and microwave absorbing materials. The SiO2 nanospheres with average diametersof 190 nm were synthesized by the hydrolysis of tetraethyl orthosilicate (TEOS), and used as the core forthefirst coating layer of TiO2 achieved by sol-gel method. Thefinal cactus-like TiO2 layer was prepared viaa hydrothermal method. The morphology of the resultant samples was characterized via transmissionelectron microscopy (TEM), scanning electron microscopy (SEM) and scanning transmission electronmicroscopy (STEM). This novel CDS SiO2@TiO2 microspheres based suspension exhibited improved ERproperties compared to conventional bare SiO2 spheres.

An Investigation of Surface Tracking Characteristics and Factors Influencing Epoxy Resin Pouring Insulation for Dry-type Reactors

Yongqiang Wang,Han Liu,Wenpeng Li,Renjie Ding 한국고분자학회 2019 Macromolecular Research Vol.27 No.3

This study aimed to understand the deterioration mechanisms of epoxy resin pouring insulation for outdoor dry-type reactors under the effect of long-term surface tracking discharge. Epoxy resin insulation boards similar to the main insulation composition of the dry-type reactor were poured as the experimental material. A tracking experimental platform of insulation materials was built using an inclined plate method. The tracking discharge characteristics and surface erosion of the insulation materials were measured and analyzed. The characteristics of partial discharge, erosion, hydrophobicity and surface roughness were measured experimentally. Surface morphology, three-dimensional morphology and Fourier infrared images at different stages during erosion of the epoxy resin insulation material were analyzed. The effect of glass fiber content on the tracking resistance to erosion was characterized. The results show that the tracking process of epoxy resin insulation material experienced initiation, stability, development and outbreak periods. The flashover discharge corresponding to the development period was the main reason for the carbonization of the insulating material. During the tracking process, with a change in surface topography and formation of surface products, the surface roughness of the material generally increased along with the surface roughness which rose fastest during the discharge outbreak period. The changes in the surface morphology and three-dimensional morphology of the epoxy resin material constitute the basis for assessing the condition of the insulation surface and development of the erosion. The discharge capacity of epoxy resin generally shows an exponential increase. Adding 20 wt% of glass fibers that are evenly distributed and have reduced exposure can improve the tracking resistance of epoxy resin insulation materials.

Multilevel Pedicle Subtraction Osteotomy for Correction of Thoracolumbar Kyphosis in Ankylosing Spondylitis: Clinical Effect and Biomechanical Evaluation

Xin Lv,Yelidana Nuertai,Qiwei Wang,Di Zhang,Xumin Hu,Jiabao Liu,Ziliang Zeng,Renyuan Huang,Zhihao Huang,Qiancheng Zhao,Wenpeng Li,Zhilei Zhang,Liangbin Gao 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

Objective: To compare the clinical outcomes and biomechanical characteristics of 1-, 2-, and 3-level pedicle subtraction osteotomy (PSO), and establish selection criteria based on preoperative radiographic parameters. Methods: Patients undergone PSO to treat ankylosing spondylitis from February 2009 to May 2019 in Sun Yat-sen Memorial Hospital of Sun Yat-sen University were enrolled. According to the quantity of osteotomy performed, the participants were divided into group A (1-level PSO, n = 24), group B (2-level PSO, n = 19), and group C (3-level PSO, n = 11). Clinical outcomes were assessed before surgery and at the final follow-up. Comparisons of the radiographic parameters and quality-of-life indicators were performed among and within these groups, and the selection criteria were established by regression. Finite element analysis was conducted to compare the biomechanical characteristics of the spine treated with different quantity of osteotomies under different working conditions. Results: Three-level PSO improved the sagittal parameters more significantly, but resulted in longer operative time and greater blood loss (p < 0.05). Greater stress was found in the proximal screws and proximal junction area of the vertebra in the model simulating 1-level PSO. Larger stress of screws and vertebra was observed at the distal end in the model simulating 3-level PSO. Conclusion: Multilevel PSO works better for larger deformity correction than single-level PSO by allowing greater sagittal parameter correction and obtaining a better distribution of stress in the hardware construct, although with longer operation time and greater blood loss. Three-level osteotomy is recommended for the patients with preoperative of global kyphosis > 85.95°, T1 pelvic angle > 62.3°, sagittal vertical alignment > 299.55 mm, and pelvic tilt+ chin-brow vertical angle > 109.6°.